On the way into work this morning, I felt a blast of cold air on my face. It was 19 degrees in Washington, unpleasant even for a few minutes. And we're going to hear next about people who spent the whole night outside in temperatures that were even lower.

Every winter, the Department of Housing and Urban Development picks a night in January for a survey of the nation's homeless. One group of particular concern is veterans in shelters or on the street. There can be thousands of them at any one time.

NPR's Quil Lawrence covers veterans for NPR News, and he was out all night with the homeless survey in New York City. Quil, where are you now?

QUIL LAWRENCE, BYLINE: I'm an East 33rd Street, in front of Public School 116, where the last of the volunteers have just strolled in and made their reports. There were thousands of volunteers across New York City. A couple hundred came to this school in Manhattan, and they spread out across the city counting the people who they found homeless out on this freezing January night.

INSKEEP: OK. So this is this Point in Time survey that HUD does, trying to figure out how many people are out there at any point in time. So where did you go in Manhattan, on the island of Manhattan, and what did you see?

LAWRENCE: So, I attached myself first to a group that was going down to Madison Square Park. And on a warmer night, there might have been more people out. There were only a few homeless people in that park. We approached them, asked them a few questions. If they wanted to go inside, offered them some services if they did. And then I went to a much busier place for the homeless, especially on a frigid night like this, which was Penn Station. And there were dozens of homeless people. And again, they were just asking simple questions: Hi, can we talk to you? Do you mind telling me if you have a place to stay tonight? Trying to get an idea of how many of these people are chronically homeless.

INSKEEP: Now, Quil, you were looking for veterans. That's what you cover. Did you find any?

LAWRENCE: I only met one tonight. He said he was a veteran. After speaking to him for a little while, he was pretty clearly mentally ill, and it was hard to tell what was fact and what was delusion. But for the purposes of this count, someone says they served in the military, then they'll count them as a veteran. And there are a lot of veterans among the homeless population.

INSKEEP: Does the Department of Veterans Affairs have any kind of reasonable count of how many veterans there are who are homeless in the course of a year, say?

LAWRENCE: That's part of what this count is all about. They figure that there are probably about 150,000 veterans out there who are homeless at any given time. They've said that maybe 12 percent of the homeless population are vets.

INSKEEP: These are veterans from any number of wars, going back, say, to Vietnam, or even earlier? Is that possible?

LAWRENCE: Yes. Predominantly Vietnam among the homeless population. Now, there is a figure of about 48,000 post-9/11 vets - that's Iraq and Afghanistan vets - who were helped out by the VA in some way last year, according to last year's statistics. And that's not to say that they're homeless, but they were either helped out for being homeless, being on the verge of homelessness. These were people that the VA felt that they had to help to keep them from slipping into life on the streets.

INSKEEP: Quil Lawrence, I know it's hard to generalize, but in your experience, what are some of the reasons that veterans become homeless?

LAWRENCE: Well, some of it's coming home to a hard economy, as many in a previous generation did and as many are now. They say that about 1 percent of those who separate from the military then flip into homelessness. There's also a large crossover with mental illness, but also some of the traumas related to combat. So it's a very complicated number, but these are some of the factors that play into it.

INSKEEP: Is the VA able to help homeless vets?

LAWRENCE: They've been showing some pretty impressive results. Since 2010, they started taking an approach called Housing First, where they just try to get people in some sort of shelter before they deal with other issues, like substance abuse or other problems. And they've shown a 24 percent drop in veterans' homelessness. That's all veterans.

Now, there still are thousands, tens of thousands of recently returning vets who are ending up close to the street or getting on the street, and they need help from the VA. And the VA is showing that it's helping a higher and higher number of these young vets.

INSKEEP: Quil, thanks very much.

LAWRENCE: Thank you, Steve.

INSKEEP: Hope you find some place warm. That's NPR's Quil Lawrence, who covers veterans. He's in New York City, and spent the night watching a Point in Time survey of the nation's homeless. Transcript provided by NPR, Copyright NPR.